Solutions of polymers of vinylidene cyanide



Patented June 10, 1952 SOLUTIONS'OFPOLYME CYANI sf F VINYLIDENE DE- Alan; E. A'rdis, Cuyahoga Falls, Ohio, assignor' to The B. F. Goodrich Company, New York, N. Y., a corporation of-New York No-Drawing. Application June 3, 1950,

- Serial-No. 166,078-

a 12 Claims;

This invention relates to no-velpolymerrsolutions, and pertains more particularly to: solutionsof. polyvinylidene' cyanide and copolymers and. interpolymers' of: vinylidene cyanide with other polymerizable materials, which solutions are very useful in the preparation of synthetic filaments and films.

A copending application, Serial No. 11,336, filed February 26, 1948, now U. SrPatent No. 2,589,294, describes methods for the preparation of highly useful polymers of vinylidene cyanide and" dis.- closes-thatpolyvinylidene cyanide of high molecular. weight, for example, in excess of 25,000is capable of being used to form excellent synthetic fibers, films and filaments. It is also known that vinylidene cyanide copolymerizes with other polymerizable materials to form high molecular weight copolymers which are also useful for preparing synthetic filaments and films. However, only a; very" few solvents for these high molecu- 1&1: Weight polymers and copolymers are known, they-being insoluble inmost all of the solvents ordinarily employed in dissolving high polymers and copolymers, including alcohols, carboxylic acids and their esters, ketones; hydrocarbons; chloroand nitro sub-stituted hydrocarbons and the like.

Accordingly, it is an object of this invention to provide a new class of solvents for polymers of vinylidene cyanide, which solvents are suitable for forming polymer solutions from which excellent". films, filaments and the like may be prepared.

It-isanother vobject of this invention to provide a new class of solventsforpolymers of vinylidene cyanide which solvents-do-not degrade. or decompose the polymer, and-- which .may be readily and;completely removedirom the filaments;,films andthe like prepared from such solutions;- Other objects will be apparent hereinafter.

It has "now-been discovered that theabove and other-objects are readily attained by the--useof disubstituted cyanamides assolvents-for the polymers; of-.viny1idene cyanide. Polymer solutions are thereby obtained which havethe'desiredyis The disubstituted cyanam'ides which are useful 55' 2; solvents. for. polymers ofvinylidene=cyanide==pos sessthe formula N'CN wherein each R is an g-aliphatic hydrocarbon rarlical. More particularlyit. is desiredthateachfibe a member. or the class consisting;of-alkyl radicals containing fromone te -four carbon atomsand alkenylradicals containing fromtwo to six car bon atoms. Included withinthe class of disub stituted cyanamides which are useful solvents-are dimethyl cyanamide,.diethylcyanamide, dipropyl cyanamide, diisopropylcyanamide, dibutyl cyanamide'; dianryl cyan'amide; dihexyl cyanamide,-- as well as other dialliyl' cyanamides dialken'y substituted cyanami'des s'uclr as" dially-l cyanainide; dimeth'al-lyl cyan'amid'e; divin yl cyan'amide'; diiso prop'en yl cyanamide, di-2"-etliallyl'- 'cyanamie and the like, as well as disubstituted cyan'amiiie's in which'theRs are different; for 'exampiezmethylallyl cyana-mide; anynumwyammme, propyl methallyl cyanam'id'e, meth'ylis'opropenyl cyanamide, and-the'like." The e'specially'preferred solvents are the dialkyl substitutedcyanaiiiid's containing from one to four-"carbon atoms such as dimethyl cyanamide, diethyllcyanamide, dipropyl: cyanamide, dibutyl: cyanamide, and the like.

N 0- special conditions or precautions-are--necessary in preparing the polymer solutions of this invention. For example solutions may beprepared eithenby adding: the polymer-to the sol-vent or.byreversing. the order of addition; Solution of the polymer occurs at room temperatur tbut is much more readily effected by heating the polymer-solvent mixture to a temperature of about 50 C. to"'70 C. solutionscontaining less than about :30 and especially: from about 8 to 20% by weight'oflpolyme'r or copolymerare-pre ferred for'useas-spinning or casting solutions}- It has been found desirable thatthe f polymer solution be stabilized against possible polymer chain degradation,- especially if they are to be kept for appreciablelengths of time before use. Suitable stabilizers include theoxides o'f sulfur, and"especially-:sulfur dioxide; as well as oi'ganic' acid anhydi'ides. Theuse of a; stabilizer not a critical expedient, however; for the solutions or vinylidene cyanide" polymers and copolymers disubstituted' cyanamid's remain relatively stable for a-periodcfiseveral days even wnen nc stabfliz' ingsubstan'ce presents A s was disclosed hereinabbveitfie 'disubstituted stituted styrenes, isobutylene, butadiene and substituted butadienes, as well as other polymerizable materials such as acrylonitrile and vinylidene chloride. The quantity of any monomer in the copolymer is not critical since it has been found that the disubstituted cyanamides will dissolve the copolymer regardless of the monomer charg ing ratios. The molecular weight of th polymers of vinylidene cyanide is likewise not critical, although as has been disclosed hereinabove the molecular weight should be in excess of 25,000 since lower molecular weight copolymers and polymers are of little practicalvalue.

The preparation of polymer solutions in accordance with the present invention as well as the use of such solutions in the spinning of filaments and the casting of films is more fully described in the following examples wherein all parts are by weight.

Example J 1,0 part of high molecular weight polyvinylidene cyanide i intimately mixed with 10 parts of dimethyl cyanamide at room temperature whereupon a clear, sirupy, viscous solution is formed. This solution is suitable for use as a spinning solution.

. When a vinylidene cyanide-vinyl acetate copolymer is substituted for polyvinylidene cyanide, the resulting solution is again clear and viscous and useful for the spinning of filaments and cast- A ing of films.

Example II A spinning solution is prepared by dissolving 0.5 part of polyvinylidene cyanide of molecular weight considerably above 25,000 in 4.0 parts of diethyl cyanamide. The mixture is then heated to a temperature of about 70 C. whereupon a water-like solution having a viscosity suitable for spinning is formed. When this solution is spun into a suitable spinning bath a strong, lustrous filament is obtained.

, Example III Another solution i prepared by dissolving a high molecular weight vinylidene cyanide-vinyl acetate copolymer in diethyl cyanamide maintained at a temperature of about 70 C. This solution is then cast onto a polished metal surface to give a clear, tough film.

Example IV Example III is repeated except that diallyl cyanamide and diisopropyl cyanamide are substituted for diethyl cyanamide. In each case a clear sirupy viscous solution suitable for spinning and casting is again obtained.

When the above examples are repeated using other disubstituted cyanamides, for example, dibutyl cyanamide, dimethallyl cyanamide or methylethyl cyanamide, the solutions obtained arein general equivalent to the solutions of the examples.

Also, the disubstituted cyanamides of the present invention may be utilized in admixture with other solvents such as acetone or methylethyl ketone, which in themselves are not solvents for polymers of vinylidene cyanide, but which together with disubstituted cyanamides in amount as little as 20% by volume or even less form excellent solvent mixtures. For example, a mixture of 50 parts of dimethyl cyanamide and 50 parts of acetone readily dissolves both polyvinylidene cyanide and copolymers of vinylidene cyanide with any of the polymerizable materials disclosed hereinabove.

Although specific examples of the invention have been described herein, it is not intended to limit the invention thereto, for numerous modifications will be apparent to those skilled in the art and are included within the scope of the appended claims.

I claim:

. 1. A solution of a polymer of vinylidene cyanide in a solvent comprising a compound of the formula wherein each R. is an aliphatic hydrocarbon radical.

2. A solution of a polymer of vinylidene cyanide, in a solvent comprising a compound of the formula wherein each R is a member of the class consisting of alkyl radicals containing from one to four carbon atoms and alkenyl radicals containing from two to six carbon atoms.

3. A solution of a polymer of vinylidene cyanide, said polymer possessing a molecular weight in excess of 25,000, in a compound of the formula wherein each R is a member of the class consisting of alkyl radicals containing from one to four carbon atoms and alkenyl radicals containing from two to six carbon atoms.

4. A solution of a polymer of vinylidene cyanide, said polymer possessing a molecular weight in excess of 25,000, in a dialkyl cyanamide, in which each alkyl radical contains from one to four carbon atoms. 5. A solution of a polymer of vinylidene cyanide, said polymer possessing a molecular weight in excess of 25,000, in a dialkenyl cyanamide, in which each alkenyl radical contains from two to six carbon atoms.

6. A solution suitable for the spinning of filaments and the casting of films, said solution comprising from 8 to 20% by weight of a polymer of vinylidene cyanide, said polymer possessing a molecular weight in excess of 25,000, dissolved in a compound of the formula 5 wherein each R is a member of the class consisting of alkyl radicals containing from one to four carbon atoms and alkenyl radicals containinl; from two to six carbonatoms.

'7. A solution of a polymer of vinylidene cyanide in dimethyl cyanamide.

8. A solution of a polymer of vinylidene cyanide in diethyl cyanamide.

9. A solution of a polymer of vinylidene cyanide in diallyl cyanamide.

10'. A solution suitable for the spinning of filaments and casting of films, said solution comprising from 8 to 20% by Weight of a vinylidene cyanide-vinyl acetate copolymer dissolved in dimethyl cyanamide.

11. A solution suitable for the spinning of filaments and the casting of films, said solution comprising from 8 to 20% by weight of a vinylidene cyanide-vinyl acetate copolymer dissolved in diethyl cyanamide.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,466,395 Dickey Apr. 5, 1949 FOREIGN PATENTS Number 7 Country Date 895,600 France Jan. 29, 1945 

1. A SOLUTION OF A POLYMER OF VINYLIDENE CYANIDE IN A SOLVENT COMPRISING A COMPOUND OF THE FORMULA 